This invention relates to preformed inserts that fit into the hollow cavities or cores of masonry building blocks, for insulation.
Various attempts have been made to insulate masonry building blocks. Included among these attempts is the manufacture of STYROFOAM.RTM. inserts that are slidable into masonry block cavities of various sizes and shapes. These foam inserts are intended to prevent the transfer of heat or cold from inexpensively constructed buildings (e.g., factories) where the buildings' inner walls are actually the "inside" face(s) of the masonry block(s). In those buildings, no inside paneling or sheetrock is attached, so the blocks have to be well insulated to prevent a large "heat" transfer.
U.S. Pat. No. 4,887,405 to Nickerson discloses various embodiments of that type of foam insert--all of which are rectangular blocks with external compression slots. In one embodiment, these external slots extend almost the entire height of the insert, being alternatively located on the front and back surfaces. The disclosed insert does not allow for lateral compression over its full height; and unless the slots are completely compressed and undamaged upon insertion, heat transfer channels, in direct contact with the air and with the conductive masonry block, are formed thereby diminishing the insulating properties of the insert.
A second embodiment, in Nickerson, also discloses external compression slots, but with interfitting edge portions which reportedly seal the inner channel of the slot. This embodiment also does not allow for lateral compression over the full height of the insert. In addition, such interfitting edge portions are extremely difficult to mold and therefore make this insert less commercially attractive.
In another, unpatented, Nickerson embodiment (not shown), external compression slots, alternatively located on the front and back surfaces, extend the entire height of the insert. While providing lateral compression over the full height of the insert, this embodiment, when fully compressed, provides open-ended, vertical internal channels. These channels act as open chimneys that allow for the uninterrupted transfer of heat via convection.
Usually, the industry practice is to apply mortar over the masonry block, after a foam insert (like Nickerson) is slid into place and the block inverted. The unpatented Nickerson insert allows the mortar to creep into the external slots, and both the patented and unpatented Nickerson inserts allow for the mortar to creep into the sides. This creates so-called "mortar" fingers that act as a thermal bridge with the adjacent block, to accelerate heat transfer via conduction.
Accordingly, it is a general object of the present invention to provide an improved insert that overcomes the deficiencies of the prior art and which achieves lateral compression over the full height of the insert while maintaining optimum thermal resistance.
It is a more specific object to provide a slightly oversized insert containing a plurality of elongated internal cavities and compression slots that emanate from the opposite faces of the insert and which operate collectively to permit lateral compression over the full height of the insert.
It is another object to provide an insert having compression slots designed such that, upon compression, the slots are effectively sealed to prevent any heat loss.
It is yet another object to provide an insert that upon compression is devoid of any open-ended channels in direct contact with the block cavity walls or with any exposed area that would permit heat transfer.